From f40478dd95cc60da3535e527f6d0f2d851bf28bf Mon Sep 17 00:00:00 2001
From: Ye Liu <yeliu@instast.com>
Date: Tue, 1 Apr 2014 17:58:07 -0400
Subject: [PATCH] Implemented LIKE operator with escape char for PropertyFilter

---
 lib/persistence.js               | 52 ++++++++++++++++++++++++++++++--
 lib/persistence.store.sql.js     | 10 ++++++
 test/browser/test.persistence.js | 24 ++++++++++++++-
 3 files changed, 82 insertions(+), 4 deletions(-)

diff --git a/lib/persistence.js b/lib/persistence.js
index d89be18..a32a652 100755
--- a/lib/persistence.js
+++ b/lib/persistence.js
@@ -1319,6 +1319,44 @@ persistence.get = function(arg1, arg2) {
       }
     }
 
+    function stringLike(s, pattern, escapeChar) {
+      escapeChar = escapeChar || '';
+
+      function isSpecial(c) {
+        return c === '%' || c === '_';
+      }
+
+      function isEscapeChar(c) {
+        return escapeChar && c === escapeChar;
+      }
+
+      function patternToRe() {
+        var re = '^';
+        var c;
+        for (var i = 0, len = pattern.length; i < len; i++) {
+          c = pattern[i];
+          if (isEscapeChar(c)) {
+            c = pattern[i + 1];
+            if (isSpecial(c) || isEscapeChar(c)) {
+              re += c;
+              i++;
+            }
+          } else if (isSpecial(c)) {
+            re += '.';
+            if (c === '%') {
+              re += '*';
+            }
+          } else {
+            re += '[' + c + ']';
+          }
+        }
+        re += '$';
+        return new RegExp(re, 'i');
+      }
+
+      return patternToRe().test(s);
+    }
+
     ////////////////// QUERY COLLECTIONS \\\\\\\\\\\\\\\\\\\\\\\
 
     function Subscription(obj, eventType, fn) {
@@ -1488,10 +1526,11 @@ persistence.get = function(arg1, arg2) {
      * @param operator the operator to compare with
      * @param value the literal value to compare to
      */
-    function PropertyFilter (property, operator, value) {
+    function PropertyFilter (property, operator, value, escapeChar) {
       this.property = property;
       this.operator = operator.toLowerCase();
       this.value = value;
+      this.escapeChar = escapeChar;
     }
 
     PropertyFilter.prototype.match = function (o) {
@@ -1529,6 +1568,12 @@ persistence.get = function(arg1, arg2) {
       case 'not in':
         return !arrayContains(value, propValue);
         break;
+      case 'like':
+        return stringLike(propValue, value, this.escapeChar);
+        break;
+      case 'not like':
+        return !stringLike(propValue, value, this.escapeChar);
+        break;
       }
     };
 
@@ -1705,12 +1750,13 @@ persistence.get = function(arg1, arg2) {
      * @param property the property to filter on
      * @param operator the operator to use
      * @param value the literal value that the property should match
+     * @param escapeChar the escape character in pattern
      * @return the query collection with the filter added
      */
-    QueryCollection.prototype.filter = function (property, operator, value) {
+    QueryCollection.prototype.filter = function (property, operator, value, escapeChar) {
       var c = this.clone(true);
       c._filter = new AndFilter(this._filter, new PropertyFilter(property,
-          operator, value));
+          operator, value, escapeChar));
       // Add global listener (TODO: memory leak waiting to happen!)
       var session = this._session;
       c = session.uniqueQueryCollection(c);
diff --git a/lib/persistence.store.sql.js b/lib/persistence.store.sql.js
index ddc7b4a..d0e53ce 100755
--- a/lib/persistence.store.sql.js
+++ b/lib/persistence.store.sql.js
@@ -561,6 +561,16 @@ function config(persistence, dialect) {
       } else {
         return aliasPrefix + '`' + this.property + "` NOT IN (" + qs.join(', ') + ")";
       }
+    } else if (this.operator === 'like' || this.operator === 'not like') {
+      var result = aliasPrefix + '`' + this.property + '` ' + this.operator.toUpperCase() + ' ' + tm.outVar('?', sqlType);
+      values.push(this.value);
+
+      if (this.escapeChar) {
+          result += ' ESCAPE ' + tm.outVar('?', sqlType);
+          values.push(this.escapeChar);
+      }
+
+      return result;
     } else {
       var value = this.value;
       if(value === true || value === false) {
diff --git a/test/browser/test.persistence.js b/test/browser/test.persistence.js
index 633dd0c..ac9d8f6 100644
--- a/test/browser/test.persistence.js
+++ b/test/browser/test.persistence.js
@@ -330,7 +330,29 @@ $(document).ready(function(){
                         equals(results.length, 2, "'in' filter test");
                         coll.filter("name", "not in", ["q", "x"]).list(function(results) {
                             equals(results.length, 24, "'not in' filter test");
-                            callback();
+                            coll.filter("name", "like", "%a%").list(function(results) {
+                                equals(results.length, 1, "'like %a%' filter test");
+                                coll.filter("name", "like", "%a").list(function(results) {
+                                    equals(results.length, 1, "'like %a' filter test");
+                                    coll.filter("name", "like", "a%").list(function(results) {
+                                        equals(results.length, 1, "'like a%' filter test");
+                                        coll.filter("name", "like", "_").list(function(results) {
+                                            equals(results.length, 26, "'like _' filter test");
+                                            coll.filter("name", "not like", "%a%").list(function(results) {
+                                                equals(results.length, 25, "'not like %a%' filter test");
+                                                coll.filter("name", "not like", "_").list(function(results) {
+                                                    equals(results.length, 0, "'not like _' filter test");
+                                                    coll.add(new Task({name: 'Task %'}));
+                                                    coll.filter("name", "like", "%!%", "!").list(function(results) {
+                                                        equals(results.length, 1, "'like with escape' filter test");
+                                                        callback();
+                                                      });
+                                                  });
+                                              });
+                                          });
+                                      });
+                                  });
+                              });
                           });
                       });
                   });